packagefs: Add automatic SYS:PACKAGE_FILE attribute

* Rename SYS:PACKAGE attribute to SYS:PACKAGE_FILE.
* Re-add SYS:PACKAGE attribute. It contains the versioned name of the
  package.

src/add-ons/kernel/file_systems/packagefs/nodes/AutoPackageAttributes.cpp

@@ -105,6 +105,14 @@ AutoPackageAttributes::GetAttributeValue(const Package* package,
 {
 	switch (attribute) {
 		case AUTO_PACKAGE_ATTRIBUTE_PACKAGE:
+		{
+			const char* value = package->VersionedName();
+			_size = strlen(value) + 1;
+			_type = B_STRING_TYPE;
+			return value;
+		}
+
+		case AUTO_PACKAGE_ATTRIBUTE_PACKAGE_FILE:
 		{
 			const char* value = package->FileName();
 			_size = strlen(value) + 1;

src/add-ons/kernel/file_systems/packagefs/nodes/AutoPackageAttributes.h

@@ -18,6 +18,7 @@ class Package;
 enum AutoPackageAttribute {
 	AUTO_PACKAGE_ATTRIBUTE_ENUM_FIRST,
 	AUTO_PACKAGE_ATTRIBUTE_PACKAGE = AUTO_PACKAGE_ATTRIBUTE_ENUM_FIRST,
+	AUTO_PACKAGE_ATTRIBUTE_PACKAGE_FILE,
 
 	AUTO_PACKAGE_ATTRIBUTE_ENUM_COUNT
 };

src/add-ons/kernel/file_systems/packagefs/util/StringConstantsPrivate.h

@@ -15,4 +15,4 @@ DEFINE_STRING_CONSTANT(kSettingsLinkName, ".settings")
 
 DEFINE_STRING_ARRAY_CONSTANT(kAutoPackageAttributeNames,
 	AUTO_PACKAGE_ATTRIBUTE_ENUM_COUNT,
-	"SYS:PACKAGE")
+	"SYS:PACKAGE", "SYS:PACKAGE_FILE")